public class MPExpression {
	public String s, pre;
	public String name;
	private static String PFX = "MP_";
	
	MPExpression (String s, String name) {
		this.s = s;
		this.pre = "";
		this.name = name;
	}
	MPExpression (String s) {
		this.s = s;
		this.pre = "";
		this.name = "";
	}
	MPExpression () {
		s = "";
		pre = "";
		name = "";
	}
	public String MPName() {
		if (name.length() > 0)
			return PFX+name;
		else
			MPException.error("String <"+s+"> does not have a name");
		return "";
	}
	public static String MPName(String var) {
		return PFX+var;
	}
}